Help creating a balanced excercise programme.

SkiMummy

I am trying to work out a reasonable exercise program, and am finding it surprisingly difficult.
There is so much advice on the Internet, so I thought it might help to hear what is working for others.

I am looking to loose weight and tone.
I am eating clean and at a reasonable deficit, and currently loosing 2-3 lbs a week (although I expect this to slow down pretty soon).
I need to loose another 35 - 40lbs to reach my ideal weight.

Right now I use my elliptical 3-4 times a week, I do around 40 mins, and keep my heart rate almost continually in the fat burning zone.
I also have a bike, and try to ride 1 - 2 times a week, although this is often with the kids, so it isn't very fast ;-)
I do a Pilates DVD once a week.
I don't have access to a pool.
My knee is a bit of a mess, and has already been replaced once :-( , so heavy weights or anything that puts undue stress on that joint is out.

Day to day I walk a bit, and also climb a lot of stairs!

Does this sound like a reasonable approach.
What would you add or change, and what has worked well for you?

Any ideas on new things to try would be very welcome.